The game is really fun. The idea of spinning the roulette wheel and increasing your odds as you level up is a clever mechanic that fits the theme really well. The art is beautiful too.
I know it's hard to add everything during a game jam, but if you decide to keep developing the project, I think it would be awesome to add an upgrade system where collecting duplicate copies of the same spell makes it stronger. Maybe placing matching spells next to each other on the roulette wheel could also increase their power, or even merge them into a stronger version when you have four of the same spell side by side. Just an idea! I also think adding more enemy variety would make the game even better.
Congratulations on a great game!